TEA PARTY HEADQUARTERS: A treehouse (interior below) comes as part of a house up for sale for $10.5 million on East 93rd Street. Photo: James Messerschmidt

TEA PARTY HEADQUARTERS: A treehouse (interior at right) comes as part of a house up for sale for $10.5 million on East 93rd Street. (
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A treehouse grows on the Upper East Side.

A historic 1866 clapboard home on sale for $10.5 million comes equipped with a bit of country nostalgia — a 14-foot-high treehouse in the back yard.

“[My daughters] thought it looked like Stuart Little lived in the treehouse. We loved it. They’d have tea parties there with their friends,” said owner Cynthia “C.C.” Rivera.

“When I bought the home, I was told that it was the only treehouse in Manhattan and that there was another one in Brooklyn,” said Rivera, ex-wife of Fox New Channel’s Geraldo Rivera, who bought the spread for $6.6 million in 2000.

When her daughters were young — Simone is now 18, and Isabella is now 20 — Rivera outfitted the treehouse with “a little, round table, chairs, stuffed animals and waterproof toys.

“The treehouse fits four girls comfortably, but six girls have been up there, too.”

The accompanying mansion is 4,372 square feet at 93rd Street near Madison Avenue and is one of only five clapboards on the Upper East Side.

It’s equipped with four bedrooms, five bathrooms, and front and rear gardens, say Corcoran Group listing brokers Wendy Sarasohn and Robert Browne.

“C.C. had tons of houseguests from all over the world, and she always threatened to put them in the treehouse if they misbehaved,” Sarasohn said.

The home also has a windowed eat-in kitchen, a wood-paneled library, a wine cellar and several wood-burning fireplaces.

Rivera had placed the house on the market briefly in 2008, for $12.5million, before withdrawing it.